Monitoring applicator rods and applicator rod nips

ABSTRACT

A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each sensor enters a nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll and each sensor generates a sensor signal upon entering the second nip. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.

RELATED APPLICATIONS

The present application is related to U.S. patent application Ser. No.14/735,716 entitled MONITORING APPLICATOR RODS filed concurrentlyherewith, U.S. patent application Ser. No. 14/735,947 entitledMONITORING MACHINE WIRES AND FELTS filed concurrently herewith, U.S.patent application Ser. No. 14/735,655 entitled MONITORING UPSTREAMMACHINE WIRES AND FELTS filed concurrently herewith, U.S. patentapplication Ser. No. 14/735,892 entitled COUNT-BASED MONITORING MACHINEWIRES AND FELTS filed concurrently herewith, and U.S. patent applicationSer. No. 14/736,010 entitled MONITORING OSCILLATING COMPONENTS filedconcurrently herewith, the disclosures of which are incorporated byreference herein in their entirety.

FIELD

The present invention relates generally to papermaking and, moreparticularly to monitoring one or more components in the papermakingprocess.

BACKGROUND

Nipped rolls are used in a vast number of continuous process industriesincluding, for example, papermaking, steel making, plastics calendaringand printing. In the process of papermaking, many stages are required totransform headbox stock into paper. The initial stage is the depositionof the headbox stock, commonly referred to as “white water,” onto apaper machine forming fabric, commonly referred to as a “wire.” Upondeposition, a portion of the white water flows through the intersticesof the forming fabric wire leaving a mixture of liquid and fiberthereon. This mixture, referred to in the industry as a “web,” can betreated by equipment which further reduce the amount of moisture contentof the finished product. The fabric wire continuously supports thefibrous web and transfers it to another fabric called a felt whichadvances it through the various dewatering equipment that effectivelyremoves the desired amount of liquid from the web. Water from the web ispressed into the wet felt and then can be removed as the wet felt passesa suction box. Dry felts can also be used to support the fibrous webthrough steam dryers.

One of the stages of dewatering is effected by passing the web through apair or more of rotating rolls which form a nip press or series thereof,during which liquid is expelled from the web via the pressure beingapplied by the rotating rolls. The rolls, in exerting force on the weband felt, will cause some liquid to be pressed from the fibrous web intothe felt. The web can then be advanced to other presses or dry equipmentwhich further reduce the amount of moisture in the web. The “nip region”is the contact region between two adjacent rolls through which the paperweb passes.

The condition of the various wires and felts can cause variations in theamount of liquid and other materials that are removed from the web whichcan, in turn, alter an amount of nip pressure applied to the web in anip region. Other components in the papermaking process such as sizeapplication stations, coating stations, doctor blades, and oscillatingshowers can also affect the characteristics of the web. Even nippressure axially along the roll is beneficial in papermaking andcontributes to moisture content, caliper, sheet strength and surfaceappearance. For example, a lack of uniformity in the nip pressure canoften result in paper of poor quality. Thus, there remains a need tomonitor various components of the papermaking process and account fortheir potential effect on nip pressure at one or more nip regions.

SUMMARY

In accordance with one aspect of the present invention a systemassociated with a sensing roll for collecting roll data includes aplurality of sensors located at axially spaced-apart locations of thesensing roll, wherein each sensor enters a region of a first nip betweenthe sensing roll and a rotating component during each rotation of thesensing roll. The system also includes an application station,comprising a rotating applicator rod with an axis of rotationsubstantially parallel to that of the sensing roll and forming a secondnip with the sensing roll, wherein each sensor enters a region of thesecond nip between the sensing roll and the applicator rod during eachrotation of the sensing roll. Further, each sensor generates arespective sensor signal upon entering a region of the second nip andthe system includes structure for generating a periodically occurringstarting reference associated with each rotation of the applicator rod.A processor receives the periodically occurring starting reference andthe respective sensor signal generated by each sensor as it movesthrough the second nip and, upon receiving the respective sensor signal,the processor operates to a) determine a particular one of the pluralityof sensors which generated the respective sensor signal, b) based upon avalue occurring between when the respective sensor signal was generatedand a most recent starting reference, identify one of a plurality oftracking segments, wherein each of the plurality of tracking segmentsis, respectively, associated with a different value, and c) store therespective sensor signal to associate the respective sensor signal withthe identified one tracking segment.

The purpose of the applicator rod is to provide an even coating in thecross direction to an applicator roll, which may comprise the sensingroll, for transfer to a web when pressed in the first nip. Both groovedand smooth rods are at times used depending upon the viscosity of thecoating and the end product. Grooved rods have alternating ridges andvalleys in which an outer surface of each ridge comes in contact withthe applicator roll in order to meter the correct amount of coatingthrough open areas, or valleys, between the applicator roll and theapplicator rod. The pressure of a grooved rod therefore may be directlymeasured by the sensing roll, when defining the applicator roll, fromthis contact. In some instance there may be a thin film, or coating,that is present between one or more of the ridges and the applicatorroll; however the sensed pressure may be considered as a directlymeasured pressure of the applicator rod. The smooth rod may also have apressure applied in a direction toward the sensing roll; however, thereshould always be a layer of coating between a smooth rod and theapplicator roll. Hence, the sensing roll can only detect the hydraulicforce transmitting through the coating from the smooth rod. The rods areheld along their cross-direction (CD) axis by a number of holders whichare adjusted to keep pressure across the CD for both the grooved rodsand the smooth rods.

Typically grooved rods are used with starch applications and theequipment is referred to as a Size Press, or press rod. Smooth rods arecommonly used for coating and the equipment is referred to as a rodcoater or coating rod. Both types of rods may rotate with a surfacevelocity different than that of the applicator roll.

In accordance with one aspect of the present invention the rotatingcomponent comprises a mating roll, a web of material travels through thefirst nip from an upstream direction to a downstream direction, and eachsensor generates a respective sensor signal upon entering a region ofthe first nip. In accordance with a different aspect, each sensorgenerates a respective sensor signal upon entering a region of thesecond nip.

In accordance with related aspects of the invention each of therespective sensor signals comprises a pressure value. In accordance withother aspects of the invention the applicator rod comprises a size pressrod or a coating rod.

In a related aspect of the present invention the processor receives therespective sensor signal for each of the plurality of sensors duringeach rotation of the sensing roll, and a plurality of the respectivesensor signals occur during a plurality of rotations of the sensingroll. For each one of the plurality of the respective sensor signals,the processor identifies an associated applicator rod axial segment andits determined one tracking segment.

In yet another related aspect, the applicator rod comprises n axialsegments, having respective index values: 1, 2, . . . , n; theapplicator rod period comprises m tracking segments, having respectiveindex values: 1, 2, . . . , m, such that there are (n times m) uniquepermutations that are identifiable by a two-element set comprising arespective axial segment index value and a respective tracking segmentindex value. A respective average pressure value can be associated witheach of the (n times m) unique permutations, each of the respectiveaverage pressure values based on previously collected pressure readingsrelated to the second nip.

In another related aspect of the present invention, the plurality oftracking segments associated with the applicator rod comprise one of a)a plurality of circumferential segments on the applicator rod or b) aplurality of time segments of a period of the applicator rod.

In accordance with another aspect of the invention, a method associatedwith a sensing roll for collecting roll data includes providing aplurality of sensors located at axially spaced-apart locations of thesensing roll, wherein each sensor enters a region of a first nip betweenthe sensing roll and a rotating component during each rotation of thesensing roll. The method also includes providing an application station,having a rotating applicator rod with an axis of rotation substantiallyparallel to that of the sensing roll and forming a second nip with thesensing roll such that each sensor enters a region of the second nipduring each rotation of the sensing roll; wherein each sensor generatesa respective sensor signal upon entering a region of the second nip. Themethod also includes generating a periodically occurring startingreference associated with each rotation of the applicator rod; andreceiving the periodically occurring starting reference and therespective sensor signal generated by each sensor. Upon receiving therespective sensor signal: a) a particular one of the plurality ofsensors which generated the respective sensor signal is determined, b)based upon a value occurring between when the respective sensor signalwas generated and a most recent starting reference, one of a pluralityof tracking segments is identified, wherein each of the plurality oftracking segments is, respectively, associated with a different value,and c) the respective sensor signal is stored to associate therespective sensor signal with the identified one tracking segment.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed that thepresent invention will be better understood from the followingdescription in conjunction with the accompanying Drawing Figures, inwhich like reference numerals identify like elements.

FIG. 1 is an end, schematic view of a nip press, in accordance with theprinciples of the present invention, showing the formation of a webnipped between the nip rolls, the nip width of the nip press beingdesignated by the letters “NW.”

FIG. 2 is a side elevation view of a sensing roll showing the placementof a line of sensors in accordance with the principles of the presentinvention.

FIG. 3 illustrates how a rotation of the sensing roll and the matingroll can change a circumferential segment of the mating roll that entersa nip region coincidentally with a sensor on each rotation of thesensing roll, in accordance with the principles of the presentinvention.

FIGS. 4A and 4B are a table of how collecting x sensor readings from asensor would be associated with the different circumferential segmentsof the mating roll, in accordance with the principles of the presentinvention.

FIG. 5 is a schematic drawing showing the basic architecture of aparticular monitoring system and paper processing line in accordancewith the principles of the present invention.

FIGS. 6, 7, and 8 depict matrices of different values that can becalculated for various axial segments and circumferential segments of amating roll in accordance with the principles of the present invention.

FIG. 9A illustrates an exemplary paper-making process or systemconfiguration in accordance with the principles of the present inventionin which each of the various circles represents a rotating component(e.g. a roll, felt, etc.) that help propels a web of material throughthe system or process.

FIG. 9B illustrates an application station in accordance with theprinciples of the present invention.

FIG. 9C and FIG. 10 illustrate details about the application station ofFIG. 9B.

FIGS. 11A1-12B illustrate a simulated data set representing collectingand averaging pressure readings at different nips at a plurality ofdistinct axial locations in a manner that is time-synchronized with aperiod of rotation of an applicator rod in accordance with theprinciples of the present invention.

FIG. 13 is a flowchart of an exemplary method of time-synchronizing datain accordance with the principles of the present invention.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, and not by way oflimitation, specific preferred embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand that changes may be made without departing from the spirit and scopeof the present invention.

The present application is related to each of the following: U.S. patentapplication Ser. No. 14/268,672 entitled METHOD AND SYSTEM ASSOCIATEDWITH A SENSING ROLL AND A MATING ROLL FOR COLLECTING ROLL DATA, filedMay 2, 2014; U.S. patent application Ser. No. 14/268,706 entitled METHODAND SYSTEM ASSOCIATED WITH A SENSING ROLL AND A MATING ROLL FORCOLLECTING DATA INCLUDING FIRST AND SECOND SENSOR ARRAYS, filed May 2,2014; and U.S. patent application Ser. No. 14/268,737 entitled METHODAND SYSTEM ASSOCIATED WITH A SENSING ROLL INCLUDING PLURALITIES OFSENSORS AND A MATING ROLL FOR COLLECTING ROLL DATA, filed May 2, 2014,the disclosures of which are incorporated by reference herein in theirentirety.

As illustrated in FIG. 1, a sensing roll 10 and a mating roll 11 definea nip 12 receiving a fibrous web 16, such as a paper web, to applypressure to the web 16. It is contemplated that, in some cases, acontinuous band felt may support the web such that the felt and the webenter the nip 12. The sensing roll 10 comprises an inner base roll 20and an outer roll cover 22. As shown in FIG. 2, a set 24 of sensors 26is disposed at least partially in the roll cover 22. The set 24 ofsensors 26 may be disposed along a line that spirals around the entirelength of the roll 10 in a single revolution to define a helicalpattern, which is a common sensor geometry arrangement for roll covers.However, the helical pattern is merely an example and any arrangement iscontemplated in which at least one sensor is placed at each axialposition, anywhere along the circumference, at which data is to becollected. Each sensor 26 can, for example, measure the pressure that isbeing exerted on the sensor when it enters a region of the nip 12between the rolls 10 and 11. In particular, the set 24 of sensors 26 maybe positioned in the sensing roll 10, for example, at different axiallocations or segments along the sensing roll 10, wherein the axialsegments are preferably equally sized. In the illustrated embodiment,there are fourteen axial segments, labelled 1-14 in FIG. 2, each havingone sensor 26 located therein. It is also contemplated that the set 24of sensors 26 may be linearly arranged so as to define a line ofsensors, i.e., all sensors reside at the same circumferential location.One of ordinary skill will readily recognize that more than fourteen, orless than fourteen, axial segments may be provided as well along with acorresponding equal number of axially-spaced sensors located on thesensing roll. Also, in the description below, each sensor 26 may bereferred to as a pressure sensor, for example, but other types ofsensors can also be contemplated such as, for example, temperaturesensors.

Because having even nip pressure is beneficial during papermanufacturing, correctly calculating and displaying the nip pressureprofile are also beneficial since any corrections or adjustments to bemade to the rotating rolls based on an inaccurate calculated nippressure profile could certainly exacerbate any operational problems.There are three primary measurements of variability. The nip pressureprofile has variability that can be termed cross-directional variabilityas it is the variability of average pressure per cross-directionposition across the nip. Another type of variability represents thevariability of the high speed measurements at each position in thesingle line of sensors. This variability represents the variability ofother equipment in the paper making process including the rotationalvariability of the mating roll, i.e., the roll nipped to the sensingroll. The third variability in the nip profile includes the variabilityof multiple sensors, discussed below, at each cross-directional positionof the roll. This variability represents the “rotational variability” ofthe sensing roll as it rotates through its plurality of sensingpositions and cannot be detected unless a plurality of sensor are usedper position.

One benefit of embedding a single set of sensors in covered rolls is tomeasure the real-time pressure profile and adjust loading pressures androll crowns or roll curvature (using, for example, internal hydrauliccylinders) to achieve a flat pressure profile. As an alternative to asingle set of sensors, two pluralities or arrays of sensors can beincluded on a sensing roll as described more fully in the earlierreferenced U.S. patent application Ser. No. 14/268,706, which isincorporated herein by reference in its entirety. The sensing roll can,for example, be separated into 14 axial segments. First and secondpluralities of sensors, respectfully, are disposed at least partially inthe roll cover. Each of the first plurality of sensors is located in oneof the 14 axial segments of the sensing roll. Likewise, each of thesecond plurality of sensors is located in one of the 14 axial segmentsof the sensing roll. Each sensor of the first plurality has acorresponding sensor from the second plurality located in a same axialsegment of the sensing roll. The first plurality of sensors can bedisposed along a line that spirals around the entire length of the rollin a single revolution to define a helical pattern. In a similar manner,the second plurality of sensors can be disposed along a line thatspirals around the entire length of the roll in a single revolution todefine a helical pattern. The first and second pluralities of sensorscan be separated from one another by 180 degrees. Each sensor measuresthe pressure that is being exerted on the sensor when it enters a regionof a nip. It is contemplated that the first and second pluralities ofsensors may be linearly arranged so as to define first and second linesof sensors, which are spaced approximately 180 degrees apart. Variousalternative configurations of a plurality of sensors are alsocontemplated. For example, a plurality of sensors could be helicallyarranged in a line that spirals, in two revolutions, around the entirelength of roll.

Typically, the sensing roll 10 and the mating roll 11 are sizeddifferently, i.e., they have a different size radially andcircumferentially. Each roll may have variations in its sizecircumferentially across the axial dimension. Further, as the rollrotates, the distance from the central axis (radial dimension) to theouter surface may vary for each axial position at the same angle ofrotation even were the circumferential dimensions to be the same foreach axial position.

For example, rolls are periodically ground which results is smallarbitrary changes in diameter from the manufacture's specification.There may also be slippage with one or more of the rolls resulting inthe sensing roll surface traveling at a speed that is different than themating roll surface. Consequently, it is rare that two rolls would haveexactly the same period of rotation or have periods that are exactharmonics.

Thus, as the sensing roll 10 and mating roll 11 travel through multiplerotations relative to one another, a particular sensor 26 may not alwaysenter the region of the nip 12 with the same circumferential portion ofthe mating roll 11 as it did in a previous rotation. This behavior canbe utilized to create data maps corresponding to the surface of themating roll 11. Different average pressure matrices, each collected andbuilt during different periods of time can be compared with one anotherto investigate how they vary from one another. Variability between thedifferent data maps can indicate possible problems with the mating roll11, such as roll surface irregularities, bearing wear, and roll flexing.Variability analysis of the sensor data may also indicate possibleproblems with upstream or downstream processing equipment, e.g.,upstream rolls, an upstream forming wire, an upstream felt, an upstreamcoating station or downstream rolls.

The sensing and mating rolls 10 and 11 may be each separated into 14axial segments. All of the axial segments on the sensing roll 10 may ormay not be of the same length, and all of the axial segments on themating roll 11 also may or may not be of the same length. In theillustrated embodiment, it is presumed that all of the axial segments onthe sensing roll 10 are of the same length and all of the axial segmentson the mating roll 11 are of the same length. The axial segments on thesensing roll 10 may be aligned with the axial segments on the matingroll 11. Furthermore, the mating roll 11 may be separated intoindividual circumferential segments such as, for example, 22circumferential segments, all of substantially the same dimension.

FIG. 3 illustrates how rotation of the sensing roll 10 and the matingroll 11 can change a circumferential segment of the mating roll 11 thatenters a nip region coincidentally with a sensor on each rotation of thesensing roll 10. FIG. 3 is presented as series of position snapshotsfrom 1 to 23 of the sensing roll 10 which also correspond to 22rotations of the sensing roll 10 and 23 rotations of the mating roll 11.The left-most portion of FIG. 3 shows a starting position (i.e., where afirst sensor reading is collected) and the right-most portion representsa position of the two rolls 10 and 11 after 22 rotations of the sensingroll 10 after the first sensor reading was collected. At the startingposition, circumferential segment #1 of the mating roll 11 is positionedin the region of the nip 12 along with the sensor 26A. The mating roll11, in this example, is rotating slightly faster than the sensing roll10 such that at a second position snapshot following a complete rotationfrom the starting position, the sensor 26A is once again positioned inthe region of the nip 12 but the mating roll 11 has rotated so thatcircumferential segment #2 is in the region of the nip 12. The values ofFIG. 3 are selected just as examples to illustrate with concrete numbersoperating principles of the present invention. In accordance with theexample values of FIG. 3, when the sensing roll had completed 22rotations, the mating roll 11 has completed 23 rotations. Thus, after 21rotations from the starting position (i.e., position #22 in FIG. 3), thesensor 26A of the sensing roll 10 has been able to collect 22 sensorreadings, presuming it collected a reading at the starting position andhas “seen” all portions of the circumference of the mating roll.Therefore, 22 circumferential segments can be selected as an examplenumber of circumferential segments. One of ordinary skill will recognizethat the mating roll 11 could be broken into more circumferentialsegments but that it would take more than 22 rotations of the sensingroll 10 to collect data from sensor 26A that corresponds to each of thedifferent circumferential segments.

It would be rare that the period of the mating roll would be an integerratio of the period of the sensing roll. Hence, it is very unlikely astationary pattern would be maintained between these rolls and thiswould tend to even out the sampling of the tracking segments.

Because the one sensor 26A enters the region of the nip 12 concurrentlywith different circumferential segments of the mating roll 11 in theillustrated embodiment, the nip pressure measured by the one sensor 26Amay vary during sequential roll rotations due to the change in pressurecaused by the mating roll 11. Aspects of the present inventioncontemplate mapping readings, or signals, from each sensor 26 of the set24 over time to see how the pressure readings, or signals, vary for eachsensor due to each sensor entering the region of the nip 12 concurrentlywith different circumferential segments of the mating roll 11. As notedabove, the mapped data may be used to determine possible problems withthe mating roll 11 and, as more fully described below, data collectioncan be performed involving possible problems related to upstream ordownstream processing equipment other than the sensing roll 10 and themating roll 11.

Hence, the present invention contemplates using sensors 26 to measurefor rotational variability that is generated by the high speed rotationof the mating roll 11 when pressure signals, or readings, from thesensors 26 are time synchronized to the mating roll position. In orderto measure for rotational variability, the mating roll 11 must have someimpact on the pressure in the nip 12 to be measured. The dominant impacton the sensed nip pressure will likely be that of the mating roll 11which directly presses against the sensing roll 10. However, it may bepossible to synchronize sensor measurements with upstream rolls whichform another nip and impact the water content and thickness of the webwhich affect the nip pressure seen by the sensing roll 10. Furthermore,as rolls (not shown) in a downstream nip may pull the web and causechanges in web tension, it may be possible to also synchronize sensormeasurements with these rolls. The sensing and mating rolls 10 and 11will be used to illustrate the principles of this invention; however allprinciples are applicable to upstream and downstream processingequipment, such as upstream and downstream rolls, an upstream coatingstation, an upstream forming wire or an upstream felt.

Continuing the example of FIG. 3, the mating roll 11 may have rotationalcharacteristics that generate, for example, a sinusoidal pressurepattern which is about 8 pounds per square inch (psi) peak-to-peak. Inthe illustrated example of FIGS. 4A and 4B, to start, the pressurepattern is “0” when circumferential segment #1 is in the region of thenip 12. FIGS. 4A and 4B are a table of how collecting 51 sensor readingsfrom sensor 26A would be associated with the different circumferentialsegments of the mating roll 11. The left column 402 is the sequentialnumber assigned to the sensor reading and the middle column 404represents a pressure reading value from sensor 26A according to thesinusoidal pattern described above. Each pressure reading value istime-synchronized with the period of rotation of the mating roll 11 byassociating that value with one of the circumferential segments of themating roll 11 that was in the region of the nip 12 when the pressurereading was sensed.

One convenient way to characterize the difference in periodicity isusing units-of-measure that measure that difference in terms of timesegments, e.g., 22 time segments in the illustrated embodiment. Thelength of each time segment is the mating roll period divided by thenumber of predefined time segments. As discussed below, the predefinednumber of time segments may correspond to a predefined number of matingroll circumferential segments. A period of the sensing roll 10 can bedescribed as being x time segments smaller/larger than a period of themating roll 11. For example, according to FIG. 3, the sensing roll 10may have a period that is 1.0 mating roll time segment more than theperiod of the mating roll 11 (equivalently, the mating roll 11 can havea period that is 1.0 mating roll time segment smaller than the period ofthe sensing roll). In such an example, as the sensing roll 10 makes onecomplete revolution, the mating roll 11 will make more than a completerevolution by an amount equal to 1.0 mating roll time segment due to ithaving a smaller period than the sensing roll 10.

As noted above, the 22 time segments of the mating roll period cancorrespond to 22 circumferential segments around the mating roll 11.Thus, even though, at a conceptual level, it is the period of the matingroll 11 that is being separated into a plurality of time segments, thatconcept can correspond to a physical circumference of the mating roll11, wherein each individual time segment of the mating roll period alsocorresponds to a circumferential segment around the mating roll 11.Accordingly, differences in rotational periods between the sensing roll10 and the mating roll 11 measured in units of “time segments” can justas easily be considered in units of “circumferential segments.” In thedescription of at least some embodiments of the present invention below,reference to “circumferential segments” is provided as an aid inunderstanding aspects of an example embodiment of the present invention.However, one of ordinary skill will recognize that “time segments” andmating roll periodicity could be utilized as well without departing fromthe scope of the present invention. The “circumferential segments” and“time segments” can also be referred to generically as “trackingsegments”; this latter term encompassing both types of segmentsassociated with the mating roll 11 and other periodic components asdescribed below.

As mentioned above, data similar to that of FIGS. 4A and 4B is capturedfor each sensor 26 of the set 24. Thus, as each sensor 26 arrives at theregion of the nip 12 and senses a pressure reading, a particular matingroll outer surface portion at an axial location corresponding to thatsensor and at one of the 22 circumferential segments of the mating roll11 will also be in the nip 12. Determining the mating roll segment thatis in the nip 12 can be accomplished in a variety of different ways. Oneway involves indexing a particular one of the 22 mating roll segmentswith a trigger signal that is fired each time the mating roll 11completes one revolution; a time period since the last trigger signalcan be used to determine which of the 22 segments (measured relative tothe indexed segment) is in the nip 12. For example, if the time betweeneach firing of the trigger signal is 220 ms, then each time segment is10.0 ms, which corresponds to one of the 22 mating roll circumferentialsegments. A pressure signal generated by a sensor 26 in the nip regionoccurring at 30 ms after the trigger signal would be assigned to timesegment 3 as three 10.0 ms segments will have passed, e.g., the nipregion, from when the trigger signal is made to when the pressure signalis generated.

In FIG. 5, a processor 903 can be present that can generate a real-timenip profile. In addition, the processor 903 can also receive a triggersignal 901 related to the rotation of the mating roll 11. As justdescribed, some circumferential segment or position 907 of the matingroll 11 can be indexed or encoded such that a signal generator 900detects the encoded segment 907 and generates the trigger signal 901each time the signal generator 900 determines that the segment 907 ofthe mating roll 11 completes another full rotation. When the mating roll11 is rotated such that the circumferential position or segment 907 isaligned with a detector portion of the signal generator 900, then theone of the 22 circumferential segments that happens to be positioned inthe nip region can arbitrarily be labeled as the first circumferentialsegment such that the other circumferential segments can be numberedrelative to this first segment. This particular rotational position ofthe mating roll 11 can be considered a reference position. As the matingroll 11 rotates, its rotational position will vary relative to thatreference position and the amount of this variance determines which ofthe 22 circumferential segments will be positioned in the nip region.Accordingly, based on the rotational position of the mating roll 11relative to that reference position a determination can be made as towhich of the 22 circumferential segments is in the nip region when aparticular sensor 26 generates a pressure signal. FIG. 5 illustrates theoverall architecture of one particular system for monitoring paperproduction product quality. The system of FIG. 5 includes the processor903, noted above, which defines a measurement and control system thatevaluates and analyzes operation of the roll 11. The processor 903comprises any device which receives input data, processes that datathrough computer instructions, and generates output data. Such aprocessor can be a hand-held device, laptop or notebook computer,desktop computer, microcomputer, digital signal processor (DSP),mainframe, server, other programmable computer devices, or anycombination thereof. The processor 903 may also be implemented usingprogrammable logic devices such as field programmable gate arrays(FPGAs) or, alternatively, realized as application specific integratedcircuits (ASICs) or similar devices. The processor 903 may calculate anddisplay the real-time average pressure profile calculated at the end ofthe prior collection session. For example, the pressure measurementsfrom the sensors 26 can be sent to a wireless receiver 905 fromtransmitter(s) 40 located on the sensing roll 10. The signals can thenbe communicated to the processor 903. It is contemplated that theprocessor 903, in addition to calculating a real-time average pressureprofile, may use the real-time average pressure profile to automaticallyadjust crown and loading mechanisms to achieve a flat pressure profile.Crown and loading mechanisms may also be adjusted manually by anoperator using information provided by the real-time average pressureprofile.

There are other ways to determine the position of the mating roll 11.One way is to use a high precision tachometer that divides the rotationof the roll 11 into a number of divisions, perhaps 440. In this example,each time segment would be 20 positions on the high precisiontachometer. All methods of determining the position of the mating rollare included in this invention.

In an example environment in which there are 14 axially arranged sensors26, each of which can be uniquely referred to using an axial segmentindex value that ranges from “1” to “14”, and there are 22circumferential segments on the mating roll 11 (or time segments), eachof which can be uniquely referred to using a tracking segment indexvalue ranging from “1” to “22”, there are 308 (i.e., 22×14=308) uniquepermutations of pairs consisting of a sensor number and acircumferential segment number (or time segment number), wherein eachpermutation is identifiable by a two-element set comprising a respectiveaxial segment index value and a respective tracking segment index value.In the illustrated embodiment, the sensor numbers also correspond to themating roll axial segments. Therefore the data collected can beconsidered a 22×14 matrix as depicted in FIG. 6. Each row of FIG. 6represents one of the 22 mating roll circumferential segments (or timesegments) and each column represents one of the 14 axially arrangedsensors 26 and, thus, each cell represents one of the possible 308permutations. Each column also corresponds to a mating roll outersurface portion at an axial location aligned with and corresponding tothe sensor 26 assigned that column. Each cell represents a combinationof a sensor number (or axial segment number) and a particular matingroll circumferential segment (or time segment). For example, cell 100represents a value that will relate to a pressure reading that occurredwhen sensor number 14 (number 14 of the 1-14 sensors defining the set24) entered the region of the nip 12 concurrently with a mating rollouter surface portion at an axial location corresponding to sensornumber 14 and mating roll circumferential segment number 1 (or timesegment number 1). Thus, each cell of the matrix represents a uniquepermutation from among all the possible permutations of different axialsegment numbers (e.g., 1-14) and circumferential segment numbers (e.g.,1-22) (or time segments 1-22). A value stored in a particular matrixelement is thereby associated with one particular permutation ofpossible axial segment numbers and circumferential segment numbers (ortime segments).

The matrix of FIG. 6 can, for example, be a “counts” matrix wherein eachcell represents the number of times a particular sensor and a particularmating roll outer surface portion at an axial location corresponding tothat sensor and a particular mating roll circumferential segment wereconcurrently in the region of the nip 12 to acquire a pressure readingvalue. FIG. 7 illustrates a similarly sized matrix (i.e., 22×14) but thevalues within the matrix cells are different from those of FIG. 6. Thecell 200 still represents a value that is related to sensor number 14(or axial segment 14, out of 1-14 axial segments, of the mating roll 11)and circumferential segment 1 but, in this example, the value is acumulative total of pressure readings, e.g., in pounds/inch, acquired bythe sensor for that circumferential segment during a plurality ofrotations of the sensing roll 10. Thus, each time sensor number 14happens to enter the region of the nip 12 along with the mating rollcircumferential segment number 1, the acquired pressure reading value issummed with the contents already in the cell 200. Each of the 308 cellsin this matrix of FIG. 7 is calculated in an analogous manner for theirrespective, associated sensors and segments.

From the matrices of FIG. 6 and FIG. 7, an average pressure matrixdepicted in FIG. 8 can be calculated. For example, cell 100 includes thenumber of pressure readings associated with sensor number 14 (or axialsegment 14 of the mating roll 11) and circumferential segment number 1while cell 200 includes the total or summation of all those pressurereadings. Thus, dividing cell 200 by cell 100 provides an averagepressure value for that particular permutation of sensor number andmating roll circumferential segment number which entered the region ofthe nip 12 concurrently.

As a result, the matrix of FIG. 8 represents an average pressure valuethat is sensed for each particular sensor number and mating rollcircumferential segment number. The length of time such data iscollected determines how many different pressure readings are used insuch calculations.

The data set out in FIGS. 4A and 4B is simulated data.

The raw pressure readings, or pressure signals, from the sensors 26 canbe affected by a variety of components in the system that move the webof material. In particular, the average values in the average pressurematrix of FIG. 8 are related to variability synchronized to the matingroll 11. However, there may be other variability components that are notsynchronized with the mating roll 11 such as variability in a crossdirection (CD), shown in FIG. 2. One measure of this CD variability iscaptured by calculating an average for each column of the averagepressure matrix. Thus, the average pressure matrix of FIG. 8 can alsoinclude a row 302 that represents a column average value. Each of the 14columns may have 22 cells that can be averaged together to calculate anaverage value for that column. For example, cell 304 would be theaverage value in the 22 cells of the second column of the averagepressure matrix.

Individual collection sessions of pressure readings to fill the matricesof FIGS. 6, 7, and 8 may be too short to build robust and completematrices due to data buffer and battery life limitations of dataacquisition systems in communication with the sensing roll 10. In suchcases, consecutive collection sessions can be combined by not zeroingthe matrices (i.e., counts and summation matrices) upon starting a newcollection session or combining the separate matrices collected in apost hoc fashion. Consequently, collections may be stopped and restartedwithout loss of data fidelity as long as the synchronization of themating roll is maintained. In particular, combining multiple collectionsessions that are separated by gaps in time can be beneficial to helppopulate the matrices. For example, if the period difference between thetwo rolls were closer to 2.001 instead of 1.0 time or circumferentialsegments, the collection would have a tendency to collect only evenlynumbered time/circumferential segments in the short term (i.e., evenlynumbered segments are those that are offset an even number of segmentsfrom a starting segment) until sufficient time has passed to move thecollection into the odd numbered time/circumferential segments.Combining collection sessions separated by a long time delay may help toshift the collection so that data is more uniformly captured for all thedifferent time/circumferential segments because there is no expectationthat the period of the mating roll will be related to arbitrary timegaps between collection sessions.

The press of FIG. 1 can be located at a number of different positionswithin the chain or serial sequence of different components that arepart of a modern paper processing operation. FIG. 9A illustrates anexemplary process and system configuration in accordance with theprinciples of the present invention in which each of the various circlesrepresents a rotating component (e.g. a roll) that helps propel a web ofmaterial 904 through the process/system. The process starts at a headbox902 where a fiber slurry is distributed over a wire mesh 906 whichallows liquid to readily drain from the slurry. From the wire mesh 906,the web of material 904 travels to a first wet felt station 908 having afelt 909 that helps dry the web of material 904. The felt 909 is acontinuous band arranged to travel in a loop pattern around a pluralityof rolls 940. In the example of FIG. 9A, there are four rolls 940. Thefelt 909 enters a press area 916 between one of the rolls 940 and asensing roll 918. The sensing roll 918 may operate similar to thesensing roll 10 of FIG. 1. Downstream from the wet felt station 908 isanother wet felt station 910 having its own felt 911 traveling in a looppattern around another set of four rolls 941. There is also a secondpress region 920 having a press roll 922, which, in the illustratedembodiment, is not a sensing roll. The last wet felt station 912 has afelt 913 traveling in a loop pattern around another set of four rolls942. The felt 913 is pressed by one of the rolls 942 and a secondsensing roll 926 in a third press region 924. The felts 909, 911, 913are pressed into the web of material in their respective press regions916, 920, 924 to absorb liquid from the web of material 904. In thismanner, the web of material 904 is drier after passing through the wetfelt stations 908, 910, 912. By “drier” it is meant that the fibers inthe web of material 904 have a higher percentage by weight of fibersafter the wet felt stations than before. Additional drying can beperformed, however, by separate dryers 914 before the web of material904 progresses further downstream in the process of FIG. 9A.

The process or system of FIG. 9A includes an application or coatingstation 950 where application material can be applied to one or bothsides of the web of material 904. In the illustrated example of FIG. 9A,the application station 950 affects both sides of the web of material904. On the left side, a first applicator roll 952 travels through atrough 954 which holds a first application material that adheres to acover of the applicator roll 952. The first applicator roll 952 and afirst applicator rod 956 form a nip 958 that changes a thickness of thefirst application material that is on the cover of the applicator roll952. The first applicator roll 952 defines a nip 970 with a secondapplicator roll 962. On the right side, the second applicator roll 962travels through a trough 964 which holds a second application material(which may or may not be different than the first material in the trough954) that adheres to a cover of the second applicator roll 962. Thesecond roll 962 and a second applicator rod 966 form a nip 968 thatchanges a thickness of the second application material that is on thecover of the roll 962. When the first and second application materialson the first and second rolls 952 and 962 enter the nip 970, the firstand second applicator rolls 952 and 962 press the first and secondapplication materials into the web of material 904. The first and secondapplication materials may comprise a conventional liquid paper surfacesizing composition. Also, one or both of the first and secondapplication materials can comprise conventional coating compositions.Example application materials are disclosed in U.S. Pat. Nos. 7,018,708;7,745,525; 8,361,573; 7,815,770; 7,608,166; 7,736,466; 7,967,953;8,372,243; 8,758,565; 7,828,935; 7,608,338; 8,007,920; 8,586,279;8,586,280; 8,574,690; 8,758,886; 8,382,946; 7,582,188; 8,123,907;8,652,593; 8,697,203; 8,652,594; 8,012,551; 8,440,053; 8,608,908;8,795,796; and 8,586,156, the disclosures of which are incorporatedherein by reference.

The applicator rods 956, 966 may be either size press rods or coatingrods. A size press rod typically has spaced apart grooves with ridgesbetween the grooves that touch the cover of the applicator roll intowhich the size press rod is pressed, with possibly a thin lubricatingfilm between the ridges and the applicator roll. The grooves helpdistribute the application material (e.g., sizing composition) in auniform manner across the cover of the roll. A coating rod typicallywill not contact the cover of the roll against which it is opposed;rather, the coating rod indirectly presses into the opposing roll bypressing onto the coating of application material that is on the coverof the roll. The coating rod helps to create a coating of applicationmaterial on the roll that is of uniform thickness. As an example, asizing composition can be applied to reduce the rate at which liquidwill penetrate the ultimately produced paper product, see previouslynoted U.S. Pat. No. 8,382,946. A coating, for example, can includematerial that will produce a change in the texture and/or color of aproduct on the side to which it is applied. One of ordinary skill willrecognize that various sizing and coating materials can be applied toone or both sides of the web of material 904 without departing from thescope of the present invention. Furthermore, one of ordinary skill willrecognize that there are a variety of different specific ways to adherea sizing composition or a coating material to a cover of a roll beforebeing metered by a press rod or coating rod. Embodiments of the presentinvention contemplate utilizing any of these techniques withoutdeparting from the scope of the present invention.

FIG. 9B illustrates details of an application station in accordance withthe principles of the present invention. The left-side first applicatorroll 952 is described by way of example but the same features can beattributed to the right-side second applicator roll 962 as well. In thediscussion below of many of the various aspects of the presentinvention, only a single side of the application station 950 may bedescribed but it is intended that the description be applicable to bothsides of the station 950.

The roll 952 rotates in a clockwise direction through a trough 954 of afirst application material 980 that becomes a portion of firstapplication material 982 that adheres to the first applicator roll 952before encountering the first applicator rod 956. The first applicatorrod 956 (e.g., coating rod or sizing rod) in this example rotates in aclockwise direction and forms the nip 958 with the first applicator roll952. The first applicator rod 956 could also be configured to rotate ina counter-clockwise direction as well. As mentioned earlier, if thefirst applicator rod 956 is a size press rod, then it will have agrooved outer surface and have ridges that typically contact the outersurface of the first applicator roll 952. If the first applicator rod956 is a coating rod with a smooth surface, then it is typically rideson top of the coating material 982 a small distance from the outsidesurface of the first applicator roll 952 such that it does not directlycontact the outside surface of the first applicator roll 952. In theembodiment illustrated in FIG. 9B, the first applicator rod 956 is acoating rod. In this embodiment, the first applicator rod 956 helps toevenly distribute the material 982 in an axial direction and define withthe first applicator roll 952 the nip 958 such that the firstapplication material 984, after passing through the nip 958, has asubstantially uniform thickness. The first applicator roll 952 continuesto rotate so that the relatively uniform application material 984 entersthe nip 970 defined between the first and second rolls 952 and 962. Therolls 952 and 962 are configured as a press station such that thematerial 984 that enters the nip 970 is pressed into the web of material904. In FIG. 9B, the example application station 950 also includes asecond applicator roll 962 that forms a nip 968 with a second applicatorrod 966. Thus, a portion 985 of a second application material 981 canadhere to the second applicator roll 962 and be uniformly distributed bythe second applicator rod 966 into a uniform coating 986 of the secondapplication material that enters a region of the nip 970 to be pressedinto the web of material 904.

The first applicator roll 952 can be a sensing roll similar to thesensing roll 10 described above. The applicator roll 952, see FIG. 9C,may have 100 axially-spaced sensors 26B, for example, which correspondto 100 different axial segments 951 of the first applicator rod 956. Assuch, a plurality of sensors 26B can be arranged around the outsidesurface of the sensing roll 952 as shown in FIG. 9C. FIG. 9C and FIG. 10illustrate details about the application station 950 of FIG. 9B. Inparticular, FIG. 9C depicts the rolls 952 and 962 along with the firstapplicator rod 956 from an overhead perspective. A hypotheticalcross-sectional view of the nip 970 is also included in FIG. 9C to showthe presence of the first application material 984, the web of material904, and the second application material 986. In FIGS. 9B and 9C, thefirst applicator rod 956 is, by way of example, illustrated as a coatingrod because it has a smooth, continuous outer surface 994 and defineswith the first applicator roll 952 the nip 958 extending along orsubstantially along the entire length of the sensing roll 952. Becauseof the angle of view in FIG. 9C, it appears that the first applicatorrod 956 and the first applicator roll 952 are in contact at the nip 958,however, as is shown in FIG. 9B, there is a layer of first applicationmaterial 984 between the rod 956 and roll 952. In operation, pressure isapplied (e.g., by a rod holder (not shown)) substantially uniformlyalong the length of the first applicator rod 956. If the firstapplicator rod 956 were, for example, a size press rod, or metering rod,then the ridges of that press rod would be substantially in contact withthe sensing roll 952 along the entire length of the nip 958 and each ofthe grooves would define a distance between the press rod and thesensing roll 952. In either case, a surface of the first applicator rod956 is beneficially a uniform distance from the outer surface of thefirst applicator (or sensing) roll 952 at the nip 958. In theillustrated embodiment, the first applicator roll 952 may comprise 100sensors 26B spaced an equal distance apart axially.

In the earlier description of the mating roll 11, it was segmented into14 axial segments to correspond to each of the sensors 26A of thesensing roll 10. Similarly, as mentioned above, the first applicator rod956 can be segmented into 100 axial segments 951 that each correspond toone of the sensors 26B on the first applicator roll 952.

The first applicator rod 956, which, in an illustrated embodiment, mayhave a diameter 953 of about ⅝ inches as compared to a diameter of about30 inches for the applicator roll 952, is typically driven by a firstdrive motor 990 on one end and a second drive motor 992 on another endthat are synchronized to cause the first applicator rod 956 to uniformlyrotate about its central axis and at a constant rotational speed. Anapplication roll may typically rotate at about 3 rotations per secondwhile an application rod may typically rotate at between about 60-90rotations per minute. However, it is believed that unequal rotationalforces imparted on the first applicator rod 956 by the drive motors maycause flexing and torsional responses that cause the distance from thesurface of the first applicator rod 956 (e.g., the valleys, or grooves,of a press rod, or an outer surface of a coating rod) to be non-uniformalong the length of the nip 958. Additionally, as sections of the firstapplicator rod 956 wear, some circumferential segments of the firstapplicator rod 956 can have different radial dimensions, as measuredfrom the rod's central axis, when compared to other circumferentialsegments. As a result of these occurrences, the uniformity of thecoating of material 984 may be imperfect and cause different amounts ofmaterial to be pressed into the web of material 904 thereby affectingthe uniformity and quality of the ultimately produced paper product.Detecting operating conditions that may indicate that non-uniformity ofthe coating of material 984 is occurring may be beneficial in improvingthe operation of application stations such as station 950.

For example, in axial locations of the nip 958 where the firstapplicator rod 956 may “lift” away from the first applicator roll 952,resulting in more application material being present at correspondingaxial locations or regions of the nip 958 than at other locations of thenip 958, a lower pressure reading may result at those axial locationswhere the rod lifted away than if no “lifting” had occurred. Conversely,in axial locations of the nip 970 where more application material ispresent than at other nip locations, the extra material will result in ahigher pressure reading than if no extra material had been present. Ifthe presence of application material at an axial location of the nip 970is considered to be indicative of the moisture content of the web ofmaterial at a corresponding region or portion of the web of materialhaving a corresponding axial location, then a pressure reading sensed atthe axial location of the nip 970 is correlated with the moisturecontent of the corresponding web of material portion having acorresponding axial and circumferential location. In other words,portions of the web of material 904 that have a higher moisture contentwill cause a higher pressure reading. However, with respect to pressurereadings sensed at different locations of the nip 958, pressure readingsand the presence of more application material are inversely correlatedsuch that lower pressure readings occur at an axial location where moreapplication material is present.

This variation in pressure readings can be used to identify that aproblem may exist with the interaction of the first applicator rod 956and the first applicator roll 952. As a result, an operator may replacethe first applicator rod 956 with a larger size rod or may change therotational speed of the first applicator rod 956. Other possiblecorrective actions could include analyzing the synchronization betweenthe drive motors 990, 992 or adjusting the holder (not shown) whichpresses the first applicator rod 956 against the first applicator roll952.

As will be discussed further below, pressure readings taken at theregion of the nip 958 at which the coating of material 984 is applied tothe first applicator roll 952 or in the region of the nip 970 defined bythe first and second applicator rolls 952 and 962 through which thecoating of material 984 is applied to a web of material 904, forexample, may be used to determine the uniformity of the coating ofmaterial 984 on the surface of the roll 952. The coating of material 984is pressed into the web of material 904 at an area 1006 of the nip 970,see FIG. 10.

It is also noted that pressure readings taken by pressure sensorsassociated with the second applicator roll 962 taken at the region ofthe nip 968 defined by the second roll 962 and the second applicator rod966 can be used to determine the uniformity of the second coatingmaterial 981 on the surface of the second roll 962.

FIG. 10 illustrates the first applicator rod 956 and the firstapplicator/sensing roll 952 arranged in alignment similar to the sensingroll 10 and the mating roll 11 of FIG. 1. The sensing roll 952 and thefirst applicator rod 956 form the nip 958 and each of the sensors 26B,100 in the illustrated embodiment, at a corresponding axial section ofthe sensing roll 952 passes through a region of the nip 958 once eachrotation of the sensing roll 952. On the first applicator rod 956, anindexed or encoded location 1004 is positioned such that each time it isadjacent a signal generator 900A it produces a time reference signalthat is communicated to a processor 903A. Accordingly, upon eachrotation of the first applicator rod 956, a new time reference signalwill be generated. Also, a wireless transceiver 40A can be included onthe first applicator/sensing roll 952 to communicate sensor readinginformation to the processor 903A. The first applicator rod 956 has acircumference that can be broken into 50 circumferential segments1002A-1002AX (in FIG. 10 only 4 such segments are explicitly labeled1002A, 1002V, 1002Y, 1002AX).

Thus, as shown in FIG. 10, the processor 903A can be present that cangenerate a real-time nip profile. In addition, the processor 903A canalso receive a trigger signal defined by the time reference signalrelated to the rotation of the first applicator rod 956. As justdescribed, some circumferential segment or position 1004 of the firstapplicator rod 956 can be indexed or encoded such that the signalgenerator 900A detects the encoded segment 1004 and generates thetrigger or time reference signal each time the signal generator 900Adetermines that the segment 1004 of the first applicator rod 956completes another full rotation. When the first applicator rod 956 isrotated such that the circumferential position or segment 1004 isaligned with a detector portion of the signal generator 900A, then theone of the 50 circumferential segments 1002A-1002AX that happens to bepositioned in the region of the nip 958 can arbitrarily be labeled asthe first circumferential segment such that the other circumferentialsegments can be numbered relative to this first segment. This particularrotational position of the first applicator rod 956 can be considered areference position. As the first applicator rod 956 rotates, itsrotational position will vary relative to that reference position andthe amount of this variance determines which of the 50 circumferentialsegments 1002A-1002AX will be positioned in the nip region. Accordingly,based on the rotational position of the first applicator rod 956relative to that reference position a determination can be made as towhich of the 50 circumferential segments 1002A-1002AX is in the nipregion when a particular sensor 26B generates a pressure signal.

As described with respect to the mating roll 11 and sensing roll 10,each sensor reading value from each of the sensors 26B on the firstapplicator/sensing roll 952 as it is in the region of the nip 958 can beassociated with one of the plurality of circumferential segments1002A-1002AX that is also concurrently in the region of the nip 958.These pressure reading values for all sensors at all of the axialsegments of the first applicator/sensing roll 952 can be collected overa period of time to build a nip profile for the nip 958.

In an example environment in which there are 100 axially arrangedsensors 26B on the first applicator/sensing roll 952, each of which canbe uniquely referred to using an axial segment index value that rangesfrom “1” to “100”, and there are 50 circumferential segments on thefirst applicator rod 956 (or time segments), each of which can beuniquely referred to using a tracking segment index value ranging from“1” to “50”, there are 5,000 (i.e., 50×100=5,000) unique permutations ofpairs consisting of a sensor number and a circumferential segment number(or time segment number), wherein each permutation is identifiable by atwo-element set comprising a respective axial segment index value and arespective tracking segment index value. In the illustrated embodiment,the sensor numbers also correspond to the press rod axial segments 951.Therefore, the data collected can be considered a 50×100 matrix similarto that depicted in FIG. 6. Each row of the 50×100 matrix represents oneof the 50 applicator rod circumferential segments (or time segments) andeach column represents one of the 100 axially arranged sensors 26B and,thus, each cell represents one of the possible 5,000 permutations. Sincethe sensor numbers correspond to the applicator rod axial segments 951,each column also corresponds to an applicator rod axial segment, i.e.,an outer surface portion of the applicator rod at an axial locationaligned with and corresponding to the sensor 26B assigned that column.Each cell represents a combination of a sensor number (or axial segmentnumber) and a particular applicator rod circumferential segment (or timesegment). Thus, each cell of a matrix similar to that of FIG. 6represents a unique permutation from among all the possible permutationsof different axial segment numbers (e.g., 1-100) and circumferentialsegment numbers (e.g., 1-50) (or time segments 1-50). A value stored ina particular matrix element is thereby associated with one particularpermutation of possible axial segment numbers and circumferentialsegment numbers (or time segments). The matrix similar to the one ofFIG. 6 can, for example, be a “counts” matrix wherein each cellrepresents the number of times a particular sensor and a particularapplicator rod outer surface portion at an axial location correspondingto that sensor and a particular rod circumferential segment wereconcurrently in the region of the nip 958 to acquire a pressure readingvalue.

Thus, similar to how a “sums” matrix of FIG. 7 and an “average” matrixof FIG. 8 were calculated, similar matrices could be calculated usingthe data collected from the first applicator/sensing roll 952 and theapplicator rod 956 regarding the nip 958. The “average” matrix providesdata that could reveal a periodically occurring pressure increase ordecrease at one or more of the rod tracking segments for a rod axialsegment as compared to other axial segments or as compared to other rodtracking segments for that particular rod axial segment. The occurrenceof such a pressure variance could be indicative of an operational issuewith the first applicator rod 956.

Similarly, a “counts” matrix, “sums” matrix and “average” matrix couldbe calculated using data collected from the first applicator/sensingroll 952 and the second applicator roll 962 regarding the nip 970, withsuch data being time synchronized to a period of rotation of the firstapplicator rod 956. Again, this “average” matrix also provides data thatcould reveal a periodically occurring pressure increase or decrease atone or more of the rod tracking segments for a rod axial segment ascompared to other rod axial segments or as compared to other rodtracking segments for that particular rod axial segment. The occurrenceof such a pressure variance could be indicative of an operational issuewith the first applicator rod 956.

As a result, one matrix can be generated that represents an averagepressure value, at the nip 958, that is sensed for each particularsensor number and press rod circumferential segment number or press rodtime-based tracking segment. Alternatively, or in addition, a secondmatrix can be generated that represents an average pressure value, atthe nip 970, that is sensed for each particular sensor number andtracking segment number of the press rod. The length of time such datais collected determines how many different pressure readings are used insuch calculations.

Thus, pressure readings at the nip 970 can be time synchronized with oneor more of the second applicator/sensing roll 962, the first applicatorrod 956, or the second applicator rod 966. Pressure readings at the nip958 can be time synchronized with the first applicator rod 956 andpressure readings at the nip 968 can be time synchronized with thesecond applicator rod 966. For example, the embodiment described withrespect to FIG. 10 happens to have the first applicator/sensing roll 952and the first applicator rod 956 define the nip 958. However, referringback to FIG. 9B, there is also a second applicator rod 966 which doesnot form a nip with the first applicator/sensing roll 952. Instead, thesecond applicator rod 966 forms a nip 968 with the second applicatorroll 962. This second applicator roll 962 may also be a sensing roll orit may be a mating roll instead without pressure sensors. Pressurereadings at various axial regions of the nip 970 are still influenced bythe second applicator rod 966 that is involved with applying the secondapplication material portion 986 to the second applicator roll 962.Thus, even though the second applicator rod 966 and the firstapplicator/sensing roll 952 do not form a nip with one another, pressurereadings at the nip 970 sensed by the first applicator/sensing roll 952can still be time-synchronized with a rotational period of the secondapplicator rod 966 using the techniques described above. Hence,variations in pressure readings taken at the nip 970 by the sensors ofthe first sensing roll 952 can be used to identify a problem that mayexist with the interaction of the second applicator rod 966 and thesecond applicator roll 962.

FIGS. 11A1-12B illustrate a simulated data set representing collectingand averaging pressure readings at the nips 958, 970 at a plurality ofdistinct axial locations in a manner that is time-synchronized with aperiod of rotation of the first applicator rod 956. Continuing with theexample embodiments described above, the first applicator rod 956 canhave its period of rotation segmented into 50 tracking segments (seeFIG. 10, 1002A-1002AX). These tracking segments could be either physicalcircumferential segments of the first applicator rod 956, as notedabove, or correspond to time-based segments of a period of rotation ofthe first applicator rod 956. Additionally, the first applicator/sensingroll 952 can include 100 axially spaced-apart sensors 26B (as shown inFIG. 9C) that correspond to 100 axial segments of the first applicatorrod 956. Each of the 100 axial segments 951 of the first applicator rod956 also corresponds to a respective axial segment of the firstapplicator/sensing roll 952.

Accordingly, a 5,000 cell matrix can be constructed that has a cell foreach permutation of a tracking segment number (e.g., 1-50) and an axialsegment number (e.g., 1-100). Pressure reading values are sensed by eachof the 100 sensors 26B in a region of the nip 958. For each pressurereading, one of the 50 tracking segments is identified based on thereference signal from signal generator 900A and the pressure readingvalue is associated with an appropriate cell of the 5,000 cell matrix.As explained above, data is collected for a period of time to capture anumber of pressure readings for each cell so that an average pressurereading can be calculated for each cell.

As described above, these tracking segments could be either physicalcircumferential segments of the first applicator rod 956 or correspondto time-based segments of a period of rotation of the first applicatorrod 956. When using time-based segments, some circumferential segment orposition 1004 of the first applicator rod 956 can be indexed or encodedsuch that a signal generator 900A detects the encoded segment 1004 andgenerates a starting reference signal each time the signal generator900A determines that the segment 1004 of the first applicator rod 956completes another full rotation. When the first applicator rod 956 isrotated such that the circumferential position or segment 1004 isaligned with a detector portion of the signal generator 900A, thestarting reference signal can be generated from which to measure, orindex, the 50 sequentially occurring time segments into which the periodof rotation of the first applicator rod 956 has been segmented. Thus, afirst time segment starting concurrently with the generation of thestarting reference signal can be considered a reference time-segment. Asthe first applicator rod 956 rotates, the number of time segments thathave transpired since the occurrence of the reference time segment willdepend on the amount of time that has transpired since generation of thereference starting signal. Accordingly, based on the number of timesegments that have occurred between a pressure reading being sensed at aregion of the nip 970 and the most recent starting reference signal, adetermination can be made as to which of the 50 time-based trackingsegment is to be associated with that pressure reading.

FIGS. 11A1-11A2 depict a simulated matrix of average pressure values foreach cell of the 5,000 cell matrix collected at the nip 958 and timesynchronized with the rotation of the first applicator rod 956. Each row1102 corresponds to one of the tracking segments of the first applicatorrod 956 and each column 1104 corresponds to one of the 100 sensors 26B(or equivalently, one of the 100 axial segments 951). Thus, each cell1106 corresponds to a unique permutation of axial segment number andtracking segment number with the value of that cell providing an averagepressure reading value at the nip 958 for that particular permutation ofnumbers. In FIGS. 11A1-11A2, the cell values happen to be measured inpounds per square inch (PSI) and for brevity, only the first 5 and last5 of the 100 sensor locations are depicted.

The sensors 26B also rotate through the nip 970 and, thus, pressurereadings can be collected that represent a pressure profile at the nip970. These pressure readings are collected in a substantially similarmanner as just described but are sensed at the nip 970 instead of (or inaddition to) the nip 958.

Accordingly, an alternative, or additional, 5,000 cell matrix can beconstructed that has a cell for each permutation of a tracking segmentnumber (e.g., 1-50) and an axial segment number (e.g., 1-100). Pressurereading values are sensed by each of the 100 sensors 26B in a region ofthe nip 970. For each pressure reading, one of the 50 tracking segmentsis identified based on the reference signal from signal generator 900Aand the pressure reading value is associated with an appropriate cell ofthe additional 5,000 cell matrix. As explained above, data is collectedfor a period of time to capture a number of pressure readings for eachcell so that an average pressure reading can be calculated for eachcell.

Unlike the behavior described above with respect to the mating roll andsensing roll of FIG. 3, the various pressures sensed at regions of thenip 970 are being collected such that they are synchronized with arotating element that does not form or define the nip 970. In otherwords, the sensed pressure readings for each axial segment aresynchronized with the period of rotation of the first applicator rod 956which does not define the nip 970. More specifically, the period ofrotation of the first applicator rod 956 can be segmented into a numberof sequentially-occurring time segments that, for example, can beindexed based on generation of a reference signal such that the “first”time segment corresponds to when the reference signal is generated andthe sequentially indexed time segments correspond to sequentiallyoccurring time segments from when the reference signal was generated.Thus, at an axial location, as each particular pressure reading issensed as a sensor at that axial segment enters a region of a nip, thatpressure reading can be associated with one of the indexed time segmentsand, more particularly, the pressure reading can be associated with thespecific time segment that is indexed by an amount of time thattranspired from when the reference signal was generated and the sensorentered the region of the nip.

As a result, at an axial segment, there may be one particularcircumferential segment of the first applicator rod 956 that is in aregion of the nip 958 when a sensor, on the first applicator roll 952,at that same axial segment enters a region of the nip 970 and senses apressure reading. Thus, when the sensor reading at a region of the nip970 is sensed there happens to be a first portion of the firstapplication material that is in the region of the nip 970 that affectsthe pressure reading and there also happens to be a second portion ofthe first application material 984 that is in contact with some physicalcircumferential segment of the first applicator rod 956. Even though thesensor reading at the region of the nip 970 will be associated with aparticular one of the tracking segments that is a fraction of the periodof rotation of the first applicator rod 956, that does not mean that thepressure reading is associated with the physical circumferential segmentof the first applicator rod 956 that was previously in the region of thenip 958 and previously in contact with the first portion of the firstapplication material 984.

FIGS. 11B1-11B2 depict a simulated matrix of average pressure values foreach cell of the additional 5,000 cell matrix collected at the nip 970and time synchronized with the rotation of the first applicator rod 956.Each row 1112 corresponds to one of the tracking segments of the firstapplicator rod 956 and each column 1114 corresponds to one of the 100sensors 26B (or equivalently, one of the 100 axial segments 951). Thus,each cell 1116 corresponds to a unique permutation of an axial segmentnumber and tracking segment number with the value of that cell providingan average pressure reading value at the nip 970 for that particularpermutation of numbers. In FIGS. 11B1-11B2, the cell values happen to bemeasured in pounds per square inch (PSI) and for brevity, only the first5 and last 5 of the 100 sensor locations are depicted.

FIG. 12A depicts a portion of the simulated data of the matrix of FIGS.11A1-11A2 but in a graphical manner. Similarly, FIG. 12B depicts aportion of the simulated data of the matrix of FIG. 11B1-11B2 but alsoin a graphical manner.

In FIG. 12A, 50 different average pressure values for three differentaxial segments are depicted. Graph 1202 represents the 50 differentvalues (i.e., the rows of FIGS. 11A1-11A2) for the 5^(th) axial segmentassociated with the first applicator rod 956 (i.e., the 5^(th) column ofFIGS. 11A1-11A2). Graph 1204 represents the 50 different values (i.e.,the rows of FIGS. 11A1-11A2) for the 50^(th) axial segment associatedwith the first applicator rod 956 (not shown in FIGS. 11A1-11A2). Graph1206 represents the 50 different values (i.e., the rows of FIGS.11A1-11A2) for the 95^(th) axial segment associated with the firstapplicator rod 956 (i.e., the 95^(th) column of FIGS. 11A1-11A2). Forexample, the graph 1202 reveals that at axial segment 5 the pressurereadings for the 50 different tracking segments tend to be between 7.5PSI and 8.5 PSI but that around tracking segment 10, the pressurereading dips below 7.5 PSI. Such a dip may indicate that the firstapplicator rod 956 is periodically lifting away from the firstapplicator roll 956 in a region of the nip 958 corresponding to axialsegment 5.

In FIG. 12B, 50 different average pressure values for three differentaxial segments are depicted. Graph 1212 represents the 50 differentvalues (i.e., the rows of FIGS. 11B1-11B2) for the 5^(th) axial segmentassociated with the first applicator rod 956 (i.e., the 5^(th) column ofFIGS. 11B1-11B2). Graph 1214 represents the 50 different values (i.e.,the rows of FIGS. 11B1-11B2) for the 50^(th) axial segment associatedwith the first applicator rod 956 (not shown in FIGS. 11B1-11B2). Graph1216 represents the 50 different values (i.e., the rows of FIGS.11B1-11B2) for the 95^(th) axial segment associated with the firstapplicator rod 956 (i.e., the 95^(th) column of FIGS. 11B1-11B2). Therelative magnitude of the pressure PSI readings in FIG. 12B as comparedto FIG. 12A show that a pressure sensed in regions of the nip 970 can bearound 5 times greater than the pressure readings sensed at regions ofthe nip 958. Also, as one example, the graph 1214 reveals that at axialsegment 50 the pressure readings for the 50 tracking segments tend to bein a range of about 44 to 45 PSI. However, around tracking segment 12 or13, the average pressure value extends upwards to about 46 PSI. A higherpressure such as this can indicate that periodically, more applicationmaterial 984 is passing through the nip 970 as a result of some periodicphenomena occurring between the first applicator rod 956 and the firstapplicator roll 952 along the region of the nip 958 corresponding toaxial segment 50.

FIG. 13 is a flowchart of an exemplary method of time-synchronizing datain accordance with the principles of the present invention. The methodbegins in step 1302 by generating a respective sensor signal from eachof a plurality of sensors located at axially spaced-apart locations of asensing roll. More particularly, each respective sensor signal isgenerated when each sensor enters a region of a first nip between thesensing roll and a press rod or a region of a second nip between thesensing roll and a mating roll during each rotation of the sensing roll.For the sensing roll and mating roll, they are located relative to oneanother to create the second nip therebetween through which a web ofmaterial passes that travels through the second nip from an upstreamdirection to a downstream direction. For the sensing roll and the pressrod, they form the first nip therebetween and are part of an applicationstation that applies either a sizing composition or coating to the coverof the sensing roll so that it is eventually pressed into the web ofmaterial. The method continues in step 1304 by generating a periodicallyoccurring time reference associated with each rotation of the press rod.Next, in accordance with the method, the respective sensor signalgenerated by each sensor is received in step 1306 whether that sensorsignal occurs based on the sensor being in the region of one of thefirst or the second nips. In step 1308, upon receiving the respectivesensor signal, the method involves three different actions: a)determining a particular one of the plurality of sensors which generatedthe respective sensor signal, b) identifying one of a plurality oftracking segments associated with the press rod based upon an amount oftime that elapsed between when the respective sensor signal wasgenerated and a most recent time reference, and c) storing therespective sensor signal to associate the respective sensor signal withthe identified one tracking segment. Of particular note, each of theplurality of tracking segments is, respectively, associated with adifferent amount of elapsed time. In accordance with the method of FIG.13, the press rod can comprise either a size press rod or a coating rod.

In addition to the time-based techniques described above for identifyingdifferent tracking segments associated with an applicator rod,alternative techniques are contemplated as well. For example, anapplicator rod could include multiple, evenly-spaced marks that could bedetected (e.g., optically) and counted as each such mark passes alocation of a sensor or detector. A reference mark could be provided andwould be distinctive from all the other marks such that when the sensordetects the reference mark, the counter circuitry resets and startscounting from an initial value (e.g., “0” or “1”). As an example, eachevenly-spaced mark could be a single tick mark, a tick mark of aparticular width, or a mark of a particular color. The reference markcould be a double-tick mark, a thicker (or thinner) tick mark, or a markof a unique color. The marks would function so as to separate theapplicator rod into different segments and a counter, or similarcircuitry, would increment a count each time a mark was detected so thatany collected data could be associated with one of the segments of theapplicator rod. Accordingly, there may be structure for generating astarting reference that includes a detector proximate to the surface ofthe applicator rod for detecting each of the plurality of markstraveling by the detector; and a signal generator in communication withthe detector for generating the starting reference each time thedistinctive reference mark is detected. Furthermore there may also be acounter in communication with the detector for counting a number of theplurality of marks that have been detected since the most recentstarting reference, wherein a value related to an amount the applicatorrod has rotated is equal to the number of the plurality of marks thathave been detected since the most recent starting reference. Also, as anexample, the generating of the starting reference can be accomplished byresetting the counter to an initial value (e.g., “0” or “1” as mentionedabove). If the techniques of segmenting the applicator rod justdescribed were utilized, then it would be unnecessary to explicitlymeasure an elapsed time since the most recent generation of a referencetiming signal that is generated each revolution of the applicator rod;instead, detection and counting of tick marks could be used to define aplurality of count-based tracking segments. In addition to being on asurface of the applicator rod, the tick marks, or similar marks oropenings, could be included on a shaft or as part of a coupling betweena drive motor and the applicator rod, thereby providing a rotary encoderbeneficial in identifying respective tracking segments. Such a“count-based” technique for synchronization of pressure data is morefully described in related patent application, application Ser. No.14/735,892, entitled COUNT-BASED MONITORING MACHINE WIRES AND FELTS,filed Jun. 10, 2015, the disclosure of which is incorporated herein byreference in its entirety.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

The invention claimed is:
 1. A system associated with a sensing roll for collecting roll data comprising: a plurality of sensors located at axially spaced-apart locations of the sensing roll, wherein each sensor enters a region of a first nip between the sensing roll and a rotating component during each rotation of the sensing roll; an application station, comprising a rotatable applicator rod forming a second nip with the sensing roll, wherein each sensor enters a region of the second nip between the sensing roll and the applicator rod during each rotation of the sensing roll; each sensor generates a respective sensor signal upon entering a region of the second nip; structure for generating a periodically occurring starting reference associated with each rotation of the applicator rod; and a processor to receive the periodically occurring starting reference and the respective sensor signal generated by each sensor as it moves through the second nip and, after receiving the respective sensor signal, the processor operates to: determine a particular one of the plurality of sensors which generated the respective sensor signal, based upon a value occurring between when the respective sensor signal was generated and a most recent starting reference, identify one of a plurality of tracking segments, wherein each of the plurality of tracking segments is, respectively, associated with a different value, and store the respective sensor signal to associate the respective sensor signal with the identified one tracking segment.
 2. The system of claim 1, wherein the rotating component comprises a mating roll, a web of material travels through the first nip from an upstream direction to a downstream direction.
 3. The system of claim 1, wherein: the starting reference comprises a time reference; the value occurring between when the respective sensor signal was generated and the most recent starting reference is calculated from an amount of time that has elapsed between when the respective sensor signal was generated and a most recent time reference; and each of the plurality of tracking segments is, respectively, associated with a different amount of elapsed time.
 4. The system of claim 1, wherein the respective sensor signal comprises a pressure value.
 5. The system of claim 1, wherein the plurality of tracking segments comprise one of: a plurality of circumferential segments on the applicator rod, and a plurality of time segments of a period of rotation of the applicator rod.
 6. The system of claim 5, wherein the processor receives: the respective sensor signal for each of the plurality of sensors during each rotation of the sensing roll, and a plurality of the respective sensor signals occurring during a plurality of rotations of the sensing roll.
 7. The system of claim 6, wherein, for each one of the plurality of the respective sensor signals, the processor identifies its identified one tracking segment and an associated applicator rod axial segment.
 8. The system of claim 7, wherein: the applicator rod comprises n axial segments, having respective index values: 1, 2, . . . , n; an applicator rod rotational period comprises m tracking segments, having respective index values: 1, 2, . . . , m, and wherein there are (n times m) unique permutations that are identifiable by a two-element set comprising a respective axial segment index value and a respective tracking segment index value.
 9. The system of claim 8, wherein, for the plurality of respective sensor signals and for one or more of the possible (n times m) permutations, the processor determines an average of all the plurality of respective sensor signals associated with an axial segment and tracking segment matching each of the one or more permutations.
 10. The system of claim 1, wherein the applicator rod comprises a plurality of optically detectable marks along at least a portion of a surface of the applicator rod, wherein one distinctive mark of the plurality of optically detectable marks is different than all of the other marks.
 11. The system of claim 10, wherein the structure for generating the starting reference comprises: a detector proximate to the surface of the applicator rod for detecting each of the plurality of optically detectable marks traveling by the detector; and a signal generator in communication with the detector for generating the starting reference each time the one distinctive mark is detected.
 12. The system of claim 11, further comprising: a counter in communication with the detector for counting a number of the plurality of marks that have been detected since the most recent starting reference, wherein the value occurring between when the respective sensor signal was generated and the most recent starting reference is equal to the number of the plurality of marks that have been detected since the most recent starting reference.
 13. The system of claim 12, wherein generating the starting reference comprises resetting the counter to an initial value.
 14. The system of claim 1, wherein the applicator rod comprises one of a size press rod and a coating rod.
 15. A method associated with a sensing roll for collecting roll data comprising: providing a plurality of sensors located at axially spaced-apart locations of the sensing roll, wherein each sensor enters a region of a first nip between the sensing roll and a rotating component during each rotation of the sensing roll; providing an application station, having a rotating applicator rod with an axis of rotation substantially parallel to that of the sensing roll and forming a second nip with the sensing roll such that each sensor enters a region of the second nip during each rotation of the sensing roll; each sensor generates a respective sensor signal upon entering a region of the second nip; generating a periodically occurring starting reference associated with each rotation of the applicator rod; and receiving the periodically occurring starting reference and the respective sensor signal generated by each sensor and, after receiving the respective sensor signal: determining a particular one of the plurality of sensors which generated the respective sensor signal, based upon a value occurring between when the respective sensor signal was generated and a most recent starting reference, identifying one of a plurality of tracking segments, wherein each of the plurality of tracking segments is, respectively, associated with a different value, and storing the respective sensor signal to associate the respective sensor signal with the identified one tracking segment.
 16. The method of claim 15, wherein the rotating component comprises a mating roll, a web of material travels through the first nip from an upstream direction to a downstream direction.
 17. The method of claim 15, wherein the respective sensor signal comprises a pressure value.
 18. The method of claim 15, wherein the plurality of tracking segments comprise one of: a plurality of circumferential segments on the applicator rod, and a plurality of time segments of a period of rotation of the applicator rod.
 19. The method of claim 18, comprising: receiving the respective sensor signal for each of the plurality of sensors during each rotation of the sensing roll, and receiving a plurality of the respective sensor signals occurring during a plurality of rotations of the sensing roll.
 20. The method of claim 19, comprising: for each one of the plurality of the respective sensor signals, identifying its identified one tracking segment and an associated applicator rod axial segment.
 21. The method of claim 20, wherein: the applicator rod comprises n axial segments, having respective index values: 1, 2, . . . , n; an applicator rod rotational period comprises m tracking segments, having respective index values: 1, 2, . . . , m, and wherein there are (n times m) unique permutations that are identifiable by a two-element set comprising a respective axial segment index value and a respective tracking segment index value.
 22. The method of claim 21, comprising: for the plurality of respective sensor signals and for one or more of the possible (n times m) permutations, determining an average of all the plurality of respective sensor signals associated with an axial segment and tracking segment matching each of the one or more permutations.
 23. The method of claim 15, wherein: the starting reference comprises a time reference; the value occurring between when the respective sensor signal was generated and the most recent starting reference is calculated from an amount of time that has elapsed between when the respective sensor signal was generated and a most recent time reference; and each of the plurality of tracking segments is, respectively, associated with a different amount of elapsed time.
 24. The method of claim 15, wherein the applicator rod comprises a plurality of optically detectable marks along at least a portion of a surface of the applicator rod, wherein one distinctive mark of the plurality of optically detectable marks is different than all of the other marks.
 25. The method of claim 24, comprising: detecting, with a detector proximate to the surface of the applicator rod, each of the plurality of optically detectable marks traveling by the detector; and generating the starting reference each time the one distinctive mark is detected.
 26. The method of claim 25, further comprising: a counter in communication with the detector for counting a number of the plurality of marks that have been detected since the most recent starting reference, wherein the value occurring between when the respective sensor signal was generated and the most recent starting reference is equal to the number of the plurality of marks that have been detected since the most recent starting reference.
 27. The method of claim 26, wherein generating the starting reference comprises resetting the counter to an initial value.
 28. The method of claim 15, wherein the applicator rod comprises one of a size press rod and a coating rod. 